Press



May 24, 1938. P. v. J. MERENDA I 2,118,098

PRESS Filed Nov. 9, 1956 Patented May 24, 1938 UNITED STATES PATENT OFFICE PRESS Paul V. J. Merenda, Fontenay-aux-Roses, France,

assignor to The Turner Tanning Machinery Company, Portland, Maine, a corporation of Maine Application November 9, 1936, Serial No. 109,824 In Germany November 29, 1935 5 Claims.

4 This invention relates to presses and is illustrated as embodied in a press particularly adapted to smooth-plating and embossing operations upon hides, skins and leather. It is to be under- 1 ,ent No. 1,932,556, granted October 31, 1933, upon application of P. V. J. Merenda.

It is an object of this invention to facilitate and expedite the return of the platen and platenoperating pistons toward their lower or initial positions in a press of the type disclosed in the said patent.

To these ends, and in accordance with an important feature of the invention, the movable platen of a press is arranged to be operated by a large piston and by a smaller piston which not only'moves the large piston during upward movement of both pistons and controls the application of pressure by the pressure medium to the larger piston, as in the-patented construction, but will also pr`ovide by its construction for release of pressure' below the large piston and also the actual discharge of the pressuremedium from the chamber below the large piston, thus facilitating and expediting the return of the large piston and of the platen carried therebyjto their'initial or lower positions. For this purpose the small piston is provided with a bore or'other passageway which extends in line with its axis the full length of the small piston, the result being that the pressure medium below the large piston may escape through. the passageway thus afforded in the small piston, this operation taking place promptly upon release of pressure in the'cylinder back of the small piston through the opening of a valve under control of the operator.

These and other features of construction and novel combinations of parts will now be pointed outn detail in the specification yand then pointed out more particularly in the appended claims.

Fig. 1 is a front view, partly in section, of the essential elements of a press illustrating one embodiment of the invention; and

Fig. 2 is a sectional view illustrating another species of the invention. i

In the illustrated press, which is` specially designed for smooth-plating and embossing operations upon hides, skins and leather, there is provided a cylinder 4 having a chamber 5 for the reception of a relatively large piston 6 having a concave upper surface for the reception of a convexly rounded portion of a vplaten member 8 having formed integrally therewith a platen III adapted to co-operate with an upper stationary platen I2 carried by a head I4. Below the large cylinder 4v is a smaller cylinder I6V having a cylinderchamber I8 which communicates with the chamber 5 of the cylinder 4. Movable in the cylinder I6 is a smaller piston 20 having extending completely therethrough a bore 24, the upper portion of the bore being restricted in size toV form a vent 26. As shown, the upper end of the piston 2D has a surface -portion around the vent 26 which is machined nat and contacts `a similar ilat surface on the lower end of the large piston 6. Hence the vent 26 is normally closed while the press is at rest and during all of the time that the pistons 6 and 20 are rising toward pressure applying position and also during all the time that pressure is being applied to a given piece of work. In addition, the upper end of the piston 20 has an annular surface 21 against which pressure may be exerted in a downward direction by the pressure medium to move this piston downwardly when pressure is removed in thechamber I8 to cause opening of the press. Extending laterally from the bore 24 of the small piston 20 are ports 28, these ports serving a purpose which will later be explained herein.

Opening into the chamber 5 of the cylinder4 is a pipe leading to avalve box 32` in which is a valve 34 normally held in closed position by a spring 36, the latter being engaged with a disk member 38 rigidly secured to stem 40 which carries the valve 34. As shown, this stem 40 of the valve 34 extends through the valve box 32 a substantial distance in an upward direction so that said valve may be controlled by a lever 42 pivoted at 44 to the upper end of a link 46 in an arrangement wherein the free end of the lever 42 is pivotally received within a socket 48 carried by a bracket 5U secured to the upper end of the large piston 6. It will be readily understood that as the large piston descends from its uppermost position, shown in Fig. 1, the lever 42 is operated to cause depression of the stem 40 and Vits valve 34 whereby the pressure medium (e. g. water or oil) Within the cylinder chamber 5 may readily escape through the pipe 30 and through a second pipe 52 to a reservoir (not shown).

Opening into the chamber I8 of the lower cyl- 2 `ing surface 21 on piston 28- (Fig. 1). 'I'he lower end of the piston 88, in Fig. 2, is screw threaded interiorly to receive a closure inember 88 which is provided with a number of `ports 68. 'As shown the closure member 88 has also an opening central therethroughY for the slidable reception of arod 18 having an enlarged head 12 which operates as a stop to limit upward movement of the small piston 88... Conveniently 'the rod 18 is extended through the lower end wall 14 of the small cylinder I8 and is provided with' a nut 18 adjustably screwed thereon and operative to hold the rod 18 at a predetermined position within the cylinder I8.

v For a'more detaileddescription of this press,

and particularly of the controller member and 'valves vwhich enable the operator to control the press, reference should be hadl to said Patent No. 1,932,5 56.j

.In` the operation of .the press shown in Fig.1, the pressure medium (usually oil or water) is introduced' into the cylinder I8 throughthepipe 54 under pressurel by a pump (not shown) upon proper.v ma'nipulatior'i of a control member for a valve, also notl shown. -While thelpl'ess was at rest, the lower end ofthe piston l28 was maintained above the level of the opening of the rpipe 8 4 by a spring device indicated t 88,- the 'arrangement being such that the large piston 8 rested upon the upper end of the small piston 28. Hence, when the pressure Ymedium is introduced under pressure into the chamber I8, the small piston is forcedupwardly carrying with it the large piston 8, there'being no escape of the pressure mediumthrough the vent 28 which is closed through the contacting surfaces on the pistons 8 and 28, as already described. During upward movement of the pistons 28y and 8, the pressure medium is drawn into the chamber 8 of the large cylinder 4 fromaI reservoir (not shown) through the pipes 8l and 52, since the valve 34 is open during practically all 'of the upward movement of the large pistn8. Atthe beginning of the pressure applying operation upon a piece oi' work between th'e platens- I8 and I2, the ports 28 in the piston 28 come into place above the floor ci the chamber .5 so that the pressure, -which up to this time has been conned to the chamber I8' of the small cylinder I8, is now transmitted through the ports 28 to the pressure medium in the chamber.-

I of the large cylinder 4, thus causing theapplication of heavy. .pressurupon the lower platen I8 due to the very much increased area,that of the lower suriaceot the large piston 8, now subjected to pressure by the pressure medium. It will be understood that the instant that pressure was applied through the ports 28 to the pressure medium in the chamber 5. the valve 84 was closed Pressure is thus maintained between-the platens I8 and I 2' for anydesired length of time. When the operator decides that the work piece has received propentreatment, a controller member (not shown) is operated to open'a release valve in a pipe leading from the chamber I8. 'This results in an instantaneousdrop in the pressure in the chamber I8 with the result that both y pistons 8 and 28 descend until ports 28 are closed.

The weight of the piston 8 and superposed platen l I8 produces, pressure in the medium in the through the bore 24 of the small piston 28.

In this way and bythe special construction of the small piston, the return of the large piston toward its lower position is substantially expedited.

Normally the piston 28 continues to descend' faster 7than the large piston 8, it being understood in this connection that, unlike piston i8, there is no packing about the piston 28, the latter having a snug running nt in the cylinder I8. However, piston 8 also descends and soon causes opening of the valve at 34 through the operation of the lever 42, thus adding another exit for the pressure medium in the chamber 5. Since the-ports 28 in the piston y28\occupy a predetermined position in the length of the said piston, it follows that the range of thicknesses of the pieces of work to be treated must be known and adhered to, it being obvious that apiece o! work thicker than this said range of thicknesses,

would prevent the ports 28 reaching operative positionand hence the desired heavy pressure could not be applied within any reasonable time through the pressure medium in the chamber 5. For this reason there has been provided another construction oi the small piston, namely, that shown in Fig.v 2, wherein the ports 84 and 88, become eiective to transmit pressure to the pressure medium inl the large chamber 5 when the small piston 68 is held from moving upwardly beyond a certain predetermined point by the head-12 of the rod 18. In this case the pressure medium passes through the ports 88 through the bore 812 .and vent 84 to the chamber 5 whereby' heavy pressure is applied to the piston 8, it be-4 ing possible to make very readily any desired adjustment or the rod 18, by proper manipulation of the nut 18, and hence of the position ofy the small piston at'which pressure will be applied to the large piston 8. In fact, the desired adjustment may be made with the press in operation. It will be understood that vsmallpiston 88 is stopped by head 12 ofrod 18 just at the instant the piece of work on the platen I8 contacts the platen I2 and before application of pressure to the work piece. Hence the pressure me-` dium may be forced through the vent 484 whereby pressure is applied in the chamber 8 to large piston 8. Otherwise, the press embodying the piston 88 operates in a manner similar to the press containing the piston 28. Upon releasing pressure in the chamber I8 (Fig. 2) to terminate a pressure applying operation, the pressure vin the chamber 5 instantly. drops substantially to that of chamber I8, since the vent 84 is uncovered when the piston,8 and platen I8 are in their uppermost pressure applyingipositions. Hence the pressure medium in chamber 5 escapes through i the passageway in the smalll piston 88 to the chamber I8. Since some portion of the pressure 'medium flows over ythe topmost surface of the piston 88 and escapes from lthe chamberv 8U downwardly through vent 84, there is a distinct tendency for the pressure in themedium about the vent 84 to drop, so that pressure on the upper ilat surface of the piston 88 is less than it would be were there no`vent.l Probably there is only small downward pressure on the topmost surface of the piston. Hence, there is an advantage in providing this piston 88 with an annular surface 65, away from the vent 6I, upon which pressure may be exerted in a downward direction by the pressure medium in the chamber 5, the pressure in the chamber being due to the weight of the piston G and superposed platen I l). 'Ihe piston 60 descends, ahead of the piston 6, by.

reason of its own weight aided bythe pressure on the surface 65. Hence the passageway in the piston 60 serves for the discharge of thel pressure medium in chamber 5, (Fig. 2,) to insure that the piston 6 may descend promptly4 to effect opening of a valve, corresponding to valve 34 (Fig. 1), whereby the medium in chamber 5 may be evacuated.

Having described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a hydraulic press, a movable platen, a cooperating platen, a large piston supporting the movable platen to operate the latter, a cylinder in which the piston is movable, a small cylinder below the large cylinder and communicating therewith, and a small piston in said small cylinder having abore extending therethrough substantially parallel to its axis, said small piston having further a ilat upper end surface to contact a similar at surface on the lower end of the large piston whereby theupper end of the bore in the small piston is closed while both pistons are in their lowermost position and also during upward movement of the pistons, caused by pressure 'behind the small piston to effect closing of the platens as a preliminary to the application of heavy pressure to the work piece in the press, and said bore in the small piston serving as a passageway for the escape oi the pressure medium from the large cylinder upon release of pressure in the small cylinder. l

2. In a hydraulic press, a movable platen, a cooperating platen, a large piston supporting the movable platen to operat-e the latter, a cylinder in which the piston is movable, a small cylinder below the large cylinder and communicating therewith, and a small piston in the small cylinder having a iiat upper end surface to contact with the flat lower end surface of the large plston when the latteris in its lowermost position, said small piston having a bore extending throughout its length and opening flush on the said upper end surface of the small piston whereby the upper end of the bore is closed bythe large piston, a pressure medium being applied under pressure to the lower end of the small piston whereby the latter is caused to rise and to lift alsothe large piston, said small piston having a port opening laterally from its bore and operative at a certain point in the upward movement of the small piston to transmit pressure from the pressure medium in the small cylinder to that in the large cylinder whereby the large piston is moved upwardly under heavy pressure substantially at the end of its upward movement, and` said bore in the small piston serving as a passageway for the escape of the pressure medium surface.

tending throughout the greater part of thelength f of said small piston with an opening onto the said iiat upper end surface of the small piston, said opening being normally closed by said large piston, a rod extending through the lower end wall of the small piston into the chamber thereof and having an enlarged end to serve as astop to limit the upward movement of the small piston, and the lower end wall of the small piston having a number. of ports furnishing permanently open passageways between said small cylinder and the chamber of the small piston whereby the pressure medium is always free to pass in one direction or the other between the small cylinder and the chamber of said small piston, the arrangement being such that the pressure medium passes promptly from the large cylinder through the small piston to the small cylinder upon .release of pressure in the small cylinder.

4. In a hydraulic press, a movable platen, a cooperating platen, a large piston to operate the movable platen, a cylinder in which the piston is movable, asmall cylinder in line with the large cylinder and communicating therewith, and a small piston movable in said small cylinder and having a passageway therethrough from one end to the other, said small piston having further a flat end surface upon which said passageway opens and adapted to contact a similar iiat surface on the adjacent end of the large piston whereby that end of said passageway in the small piston is closed while both pistons are moving together, and said small piston having also an annular surface at the same end as the said at surface and at one side of the plane of said fiat 5. In a hydraulic press, a movable platen, a 'b cooperating platen, a large piston supporting the movable platen to operate the latter, a cylinder in which the piston is movable, a small cylinder below the large cylinder and communicating' therewith, and a small piston in said small cylin- 

